Synthesis Of Transition Metal-doped Carbon Materials Catalysts And Application Of Pollutants Degradation

As heterogeneous catalyst,carbon material has been widely used in persulfate（PMS）activation.The reasonable design of its composition and structure is the key to achieve high catalytic performance.In this study,bamboo like nitrogen-containing carbon nanotubes（Ni-NCNTs）loaded with transition metal Ni and nitrogen-containing carbon nanomaterials（Fe-NC、Co-NC）loaded with transition metals Fe and Co were prepared by polymer pyrolysis and template method.They were applied to sulfate radical based–advanced oxidation processes（SR-AOPs）to activate PMS and degrade the micro pollutants bisphenol A（BPA）,norfloxacin（NOR）and sulfamethoxazole（SMX）in water respectively.At the same time,the morphology of the material was characterized and the possible degradation mechanism was explored.The main conclusions are as follows:（1）Degradation of BPA by bamboo like nitrogen-containing carbon nanotubes loaded with transition metal Ni activated PMS.Bamboo like nitrogen-containing carbon nanotubes（Ni-NCNTs）loaded with transition metal Ni were synthesized by simple polymer pyrolysis.The high specific surface area and small nano size of Ni-NCNTs provide excellent catalytic performance in the range of p H 3.0-11.0.Under the conditions of p H₀ 10.0,catalyst concentration 0.10 g/L and PMS concentration 0.30 g/L,the Ni-NCNTs/PMS system achieved the best degradation effect of 100.00%for BPA in 6 minutes and 56.70%TOC removal in 180minutes effect.The removal rates of BPA in river and lake water were 98.60%and 97.71%.Under the same conditions,Ni-NCNTs/PMS system can also efficiently degrade sulfaisoxazole,Rhodamine B and tetrabromobisphenol A.The doping of metallic Ni enables low cost and easy recycling of magnetic separation.After five cycles,the degradation rate can still reach 80.41%,which proves that Ni-NCNTs catalyst has good stability,reusability and mineralization.O₂^·–and ¹O₂ have been proved to be the main reactive oxygen species involved in the reaction in Ni-NCNTs/PMS system.（2）Degradation of NOR by PMS activated by nitrogen-containing carbon nanomaterials loaded with transition metal Co.Transition metal Co-loaded nitrogen-containing carbon nanomaterials（Co-NC）were prepared by encapsulating polydopamine（PDA）on cuttlefish bone powder by a stencil method,and used as a heterogeneous catalyst to activate PMS and degrade the quinolone antibiotic NOR.The removal of the cuttlebone powder stencil and the wrapping of the PDA layer make the material have a rough surface and a sheet-like structure,with a large specific surface area and excellent catalytic performance.The Co-NC/PMS system achieved the best degradation effect of 99.20%on NOR under the conditions of p H₀ 5.0,catalyst concentration of 0.15 g/L and PMS concentration of 0.40 g/L.The degradation rate can still reach 91.77%after five cycles.The removal rate of pharmaceutical wastewater spiked with nor was 98.63%.It is shown that Co-NC catalyst has excellent degradation performance,reusability,and practical wastewater application ability.Under the same conditions,the Co-NC/PMS system also achieved good degradation effect on BPA,ciprofloxacin and sulfisoxazole.The degradation process involves both free radical and non-free radical pathways.·OH、SO₄^·–and ¹O₂participate in the reaction process as reactive oxygen species.（3）Degradation of SMX by PMS activated by nitrogen-containing carbon nanomaterials loaded with transition metal Fe.Nitrogenous carbon nanomaterials（Fe-NC）loaded with transition metal Fe were prepared by a template method and used as a heterogeneous catalyst to activate PMS and degrade sulfonamide antibiotics SMX.The stencil method enables Fe-NC to have an irregular layered structure with good catalytic degradation performance in the range of p H3.0-11.0.The Fe-NC/PMS system achieved 95.23%degradation rate of SMX under the conditions of p H₀ 6.0,catalyst concentration 0.10 g/L,and PMS concentration 0.40 g/L.The removal rate of pharmaceutical wastewater spiked with SMX was 98.50%.The degradation rate of SMX by Fe-NC/PMS system reached 90.50%after five cycles.It is proved that Fe-NC catalyst has excellent degradation performance,reusability and practical wastewater application ability.Under the same conditions,Fe-NC/PMS system also achieved better degradation effect on BPA,NOR and tetrabromobisphenol A.¹O₂participate in the reaction process as reactive oxygen species.